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As Arctic melt accelerates, Bering Sea stands out as icy anomaly

The National Oceanic and Atmospheric Administration has released its annual Arctic Report Card, and nearly all of the data points to a warming North, with increasing plant life above the Arctic circle, less sea ice and snow, and an increased likelihood of fire and permafrost melt.

NOAA notes the sea ice melt delivered a new record low of polar ice before freezing resumed but also notes an unexplained anomaly seen over the last few years: record levels of sea ice in Alaska’s Bering Sea.

Royal Dutch Shell, hoping to resume offshore oil drilling in the Arctic waters of Alaska this year, encountered the stubborn Bering Sea ice first hand. It delayed the arrival of necessary equipment to the north to the Beaufort Sea and Chukchi Sea. According to Kathleen Cole at the sea-ice desk with the National Weather Service, the last decade has seen more ice in the Bering Sea than usual. But 2011 was especially unusual.

“Seven of the last 10 winters have been extreme in the Bering,” Cole said, “meaning that we saw more ice than what we would normally expect. Last year, we saw ice at extents that we, in our records, have never seen before, that fishermen out there had never seen before, that Natives out there had never seen before.”

But while the attention is focused on the melting sea ice and ice sheets in the Arctic -- and to a lesser extent the record growth of ice on the opposite side of the world in Antarctica -- very little attention has been paid to the Bering Sea's stubborn ice. And that means an explanation for the sea ice surge in western and northwest Alaska hasn’t been forthcoming.

“Most of the people that are looking at ice in a research vein right now are looking at how little ice there is in the summer rather than the maximums that we’ve had in the winter,” Cole said.

“Extent remained below normal in the Baffin Bay and Hudson Bay, but ice extent in the Bering Sea by the end of the month was greater than average, continuing a pattern seen in recent years,” the report said.

Regardless of the activity in the Bering Sea, the rest of NOAA’s report card paints an increasingly warm portrait of a more temperate Arctic. Among the other highlights:

Warming permafrost: Many of Alaska’s permafrost observatories, some with data going back several decades, are seeing new record high temperatures. “Only two coastal sites show exactly the same temperature as in 2011, the report notes. Areas of colder permafrost in Canada and Russia are also warming more quickly.

Increasing vegetation: In the past 30 years, green vegetation has increased more than 15 percent in the North American Arctic and 8 percent in the Eurasian Arctic, the report said. Moss and lichen growth is on the decline, and the new greenery may have another side effect, as well; increasing thunderstorms in the Arctic have “created conditions that favor a more active Arctic fire regime.”

Algal blooms: As multi-year sea ice declines, the overall Arctic ice sheet thins, leading to increased light in the waters beneath the ice sheet. This, in turn, seems to help the growth of phytoplankton around the edges of, and even within, the ice sheet. “A unique marine habitat containing abundant algal species in so-called ‘melt holes’ was observed for the first time in perennial sea ice in the central Arctic Ocean,” the report said.

Snow: Despite snowy storms in Eurasia, the overall Arctic snow cover in 2012 was one of the fastest melting on record.